Your tribe is the set of all people that (a) you consider to be part of your tribe and (b) who consider you to be part of their tribe.

This isn’t a theoretical construct. You can actually enumerate your tribe members from your social graph.

Exercise: to what extent does your tribe correspond to national borders?

I guess we could construct our tribe via Tinder-like app where you see your friends and both parties need to swipe right to get a match

Building @kiwi 
Writing @ https://kanfa.macbudkowski.com/

probably can be constructed right now by calculating who replies to who, who likes whose cast, who follows who, needs precise criteria for "establishing edge between node"